1. Field of the Invention
This disclosure relates to wireless telephony in general, and, in particular, to addition of scanning capability to a cellular telephone.
2. Description of the Related Art
Wired and wireless communication of voice, data, and images is increasing with expanding capabilities of networks and consumer devices, principally cellular phones. Business users and consumers alike employ a combination of wired and cellular telephones, facsimile, document scanners, voice, and text messaging to communicate with each other.
Modern cellular phones (commonly called, “cell phones”) have voice, text, and low-resolution imaging capability, with integral cameras. Like text messages, these pictures can be transmitted to other cellular phones or email addresses. Alternatively the images can be saved to the cellular phone memory.
The resolution of most current cellular phone cameras is 640 (horizontal)×480 (vertical) pixels, or less. The low resolution and lack of close-focus capability make these cameras unsuitable for imaging text documents. For good text legibility, a typical Group 3 facsimile scan of an 8.5×11 inch document is at about 200 dots per inch (DPI), yielding 1728 pixels across the 8.5-inch document width. A camera (oriented vertically to image an entire page) with only 480 pixels across this same dimension would provide unacceptable results, even if the camera optics were capable of accurately focusing on the document. Camera modules with higher resolution are becoming available, but still lack the resolution needed to clearly image a document.
Linear scanners capable of 200 DPI and higher are widely used in flatbed scanners and facsimile machines. The document to be scanned is either moved past the linear scanner (typical in facsimile machines) or the scanner is moved past the document (typical in flatbed scanners). Both flatbed scanners and facsimile machines are widely used by business users and consumers. Portable scanners have been developed which are manually moved across a document to be scanned, in one or more passes depending on the scanner width and size of the document. These portable scanners typically have internal memory for storing the images scanned, which can later be transferred to a PC.